Packaging and interconnection of contact structure

ABSTRACT

A packaging and interconnection for connecting a contact structure to an outer peripheral component with a short signal pass length to achieve a high frequency operation. The packaging and interconnection is formed of a contact structure made of conductive material and formed on a contact substrate, a contact trace formed on the contact substrate and electrically connected to the contact structure at one end, and the other end of the contact trace is provided with a contact pad for establishing packaging and interconnection from an upper surface thereof, a contact target provided at an outer periphery of the contact structure, a conductive lead for electrically connecting an upper surface of the contact pad and the contact target, an elastomer provided under said contact substrate for allowing flexibility in the interconnection and packaging of the contact structure, and a support structure provided between the elastomer and the PCB substrate for supporting the contact structure, contact substrate and elastomer. The contact structure is projected from the contact substrate to a free space to allow free movements of at least a horizontal portion and a contact portion thereof.

FIELD OF THE INVENTION

This invention relates to an electronic packaging and interconnection ofa contact structure, and more particularly, to an electronic packagingand interconnection for mounting a contact structure on a probe card orequivalent thereof which is used to test semiconductor wafers,semiconductor chips, packaged semiconductor devices or printed circuitboards and the like with increased accuracy, density and speed.

BACKGROUND OF THE INVENTION

In testing high density and high speed electrical devices such as LSIand VLSI circuits, high performance probe contactors or test contactorsmust be used. The electronic packaging and interconnection of a contactstructure of the present invention is not limited to the application oftesting and burn-in of semiconductor wafers and die, but is inclusive oftesting and burn-in of packaged semiconductor devices, printed circuitboards and the like. However, for the convenience of explanation, thepresent invention is described mainly with reference to a probe card tobe used in semiconductor wafer testing.

In the case where semiconductor devices to be tested are in the form ofa semiconductor wafer, a semiconductor test system such as an IC testeris usually connected to a substrate handler, such as an automatic waferprober, to automatically test the semiconductor wafer. Such an exampleis shown in FIG. 1 in which a semiconductor test system has a test head100 which is ordinarily in a separate housing and electrically connectedto the test system through a bundle of cables. The test head 100 and thesubstrate handler 400 are mechanically connected with one another bymeans of a manipulator 500 and a drive motor 510 own in FIG. 1. Thesemiconductor wafers to be tested are automatically provided to a testposition of the test head by the substrate handler.

On the test head, the semiconductor wafer to be tested is provided withtest signals generated by the semiconductor test system. The resultantoutput signals from the semiconductor wafer under test are transmittedto the semiconductor test system wherein they are compared with expecteddata to determine whether IC circuits on the semiconductor waferfunction correctly or not.

As shown in FIG. 2, the test head and the substrate handler areconnected with an interface component 140 consisting of a performanceboard 120 which is typically a printed circuit board having electriccircuit connections unique to a test head's electrical footprint, suchas coaxial cables, pogo-pins and connectors. The test head 100 includesa large number of printed circuit boards 150 which correspond to thenumber of test channels (tester pins). Each of the printed circuitboards 150 has a connector 160 to receive a corresponding contactterminal 121 of the performance board 120. In the example of FIG. 2, a“frog” ring 130 is mounted on the performance board 120 to accuratelydetermine the contact position relative to the substrate handler 400.The frog ring 130 has a large number of contact pins 141, such as ZIFconnectors or pogo-pins, connected to contact terminals 121, throughcoaxial cables 124.

FIG. 2 further shows a structure of the substrate handler 400, the testhead 100 and the interface component 140 when testing a semiconductorwafer. As shown in FIG. 2, the test head 100 is placed over thesubstrate handler 400 and mechanically and electrically connected to thesubstrate handler through the interface component 140. In the substratehandler 400, a semiconductor wafer 300 to be tested is mounted on achuck 180. A probe card 170 is provided above the semiconductor wafer300 to be tested. The probe card 170 has a large number of probecontactors (contact structures) 190, such as cantilevers or needles, tocontact with circuit terminals or contact targets in the IC circuit ofthe semiconductor wafer 300 under test.

Electrical terminals or contact receptacles of the probe card 170 areelectrically connected to the contact pins 141 provided on the frog ring130. The contact pins 141 are also connected to the contact terminals121 of the performance board 120 via the coaxial cables 124 where eachcontact terminal 121 is connected to the printed circuit board 150 ofthe test head 100. Further, the printed circuit boards 150 are connectedto the semiconductor test system main frame through the cable bundle 110having several hundreds of cables therein.

Under this arrangement, the probe contactors 190 contact the surface ofthe semiconductor wafer 300 on the chuck 180 to apply test signals tothe IC chips in the semiconductor wafer 300 and receive the resultantsignals of the IC chips from the wafer 300. The resultant output signalsfrom the semiconductor wafer 300 under test are compared with theexpected data generated by the semiconductor test system to determinewhether the IC chips in the semiconductor wafer 300 properly perform theintended functions.

FIG. 3 is a bottom view of the probe card 170 of FIG. 2. In thisexample, the probe card 170 has an epoxy ring on which a plurality ofprobe contactors 190 called needles or cantilevers are mounted. When thechuck 180 mounting the semiconductor wafer 300 moves upward in FIG. 2,the tips of the cantilevers 190 contact the pads or bumps on the wafer300. The ends of the cantilevers 190 are connected to wires 194 whichare further connected to transmission lines (not shown) formed in theprobe card 170. The transmission lines in the probe card 170 areconnected to a plurality of electrodes 197 which contact the pogo pins141 of FIG. 2.

Typically, the probe card 170 is structured by a multi-layer ofpolyimide substrates having ground planes, power planes, signaltransmission lines on many layers. As is well known in the art, each ofthe signal transmission lines is designed to have a characteristicimpedance such as 50 ohms by balancing the distributed parameters, i.e.,dielectric constant of the polyimide, inductances, and capacitances ofthe signal within the probe card 170. Thus, the signal transmissionlines are impedance matched to achieve a high frequency transmissionbandwidth to the wafer 300. The signal transmission lines transmit smallcurrent during a steady state of a pulse signal and large peak currentduring a transition state of the device's outputs switching. Forremoving noise, capacitors 193 and 195 are provided on the probe card170 between the power and ground planes.

An equivalent circuit of the probe card 170 is shown in FIGS. 4A-AE toexplain the limitations of bandwidth in the conventional probe cardtechnology. As shown in FIGS. 4A and 4B, the signal transmission line onthe probe card 170 extends from the electrode 197, the strip line(impedance matched line) 196, the wire 194 and the needle (cantilever)190. Since the wire 194 and needle 190 are not impedance matched, theseportions function as an inductor L in the high frequency band as shownin FIG. 4C. Because of the overall length of the wire 194 and needle 190is around 20-30 mm, the significant frequency limitation is resulted intesting a high frequency performance of a device under test.

Other factors which limit the frequency bandwidth in the probe card 170reside in power and ground needles shown in FIGS. 4D and 4E. If a powerline can provide large enough currents to the device under test, it willnot seriously limit the operational bandwidth in testing the device.However, because the series connected wire 194 and needle 190 forsupplying the power to the device under test are equivalent to theinductors as shown in FIG. 4D, which impede the high speed current flowin the power line. Similarly, because the series connected wire 194 andneedle 190 for grounding the power and signals are equivalent to theinductors as shown in FIG. 4E, the high speed current flow is impeded bythe wire 194 and needle 190.

Moreover, the capacitors 193 and 195 are provided between the power lineand the ground line to secure a proper performance of the device undertest by filtering out the noise or surge pulses on the power lines. Thecapacitors 193 have a relatively large value such as 10 μF and can bedisconnected from the power lines by switches if necessary. Thecapacitors 195 have a relatively small capacitance value such as 0.01 μFand fixedly connected close to the DUT. These capacitors serve thefunction as high frequency decoupling on the power lines, which alsoimpede the high speed current flow in the signal and power lines.

Accordingly, the most widely used probe contactors as noted above arelimited to the frequency bandwidth of approximately 200 MHz which isinsufficient to test recent semiconductor devices. It is considered, inthe industry, that the frequency bandwidth be of at least that equal tothe tester's capability which is currently on the order of 1 GHz orhigher, will be necessary in the near future. Further, it is desired inthe industry that a probe card is capable of handling a large number ofsemiconductor devices, especially memories, such as 32 or more, inparallel (parallel test) to increase test throughput.

To meet the next generation test requirements noted above, the inventorsof this application has provided a new concept of contact structure inthe U.S. application Ser. No. 09/099,614 “Probe Contactor Formed byPhotolithography Process” filed Jun. 19, 1998 now abandoned. The contactstructure is formed on a silicon or dielectric substrate through aphotolithography process. FIGS. 5 and 6A-6C show the contact structurein the above noted application. In FIG. 5, all of the contact structures30 are formed on a silicon substrate 20 through the samephotolithography process. The silicon substrate 20 having the contactstructures 30 may be mounted on a probe card such as shown in FIGS. 2and 3. When the semiconductor wafer 300 under test moves upward, thecontact structures 30 contact corresponding contact targets (electrodesor pads) 320 on the wafer 300.

The contact structure 30 on the silicon substrate 20 can be directlymounted on a probe card such as shown in FIG. 3, or molded in a package,such as a traditional IC package having leads, so that the package ismounted on a probe card. In the above noted patent application by theinventors, such technologies of packaging and interconnection of thecontact structure 30 with respect to the probe card or equivalentthereof is not described.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide apackaging and interconnection of a contact structure with respect to aprobe card or equivalent thereof to be used in testing a semiconductorwafer, packaged LSI and the like.

It is another object of the present invention to provide a packaging andinterconnection of a contact structure with respect to a probe card orequivalent thereof to achieve a high speed and frequency operation intesting a semiconductor wafer, packaged LSI and the like.

It is a further object of the present invention to provide a packagingand interconnection of a contact structure with respect to a probe cardor equivalent thereof wherein the packaging and interconnection isformed at an upper surface (top) of the contact structure.

It is a further object of the present invention to provide a packagingand interconnection of a contact structure which is established througha bonding wire, a tape automated bonding (TAB), and a multi-layer TAB.

It is a further object of the present invention to provide a packagingand interconnection of a contact structure which is formed between acontact trace provided at the upper surface of the contact structure anda connector.

It is a further object of the present invention to provide a packagingand interconnection of a contact structure which is formed between acontact trace provided at the upper surface of the contact structure andan interconnect pad of a printed circuit board through a solder bump.

It is a further object of the present invention to provide a packagingand interconnection of a contact structure which is formed between acontact trace provided at the upper surface of the contact structure andan interconnect pad of a printed circuit board through a conductivepolymer.

In the present invention, an electronic packaging and interconnection ofa contact structure to be used in a probe card or equivalent thereof totest semiconductor wafers, semiconductor chips, packaged semiconductordevices or printed circuit boards and the like is established between acontact trace formed at an upper surface of the contact structure andvarious types of connection means on the probe card.

In one aspect of the present invention, a packaging and interconnectionof a contact structure is comprised of: a contact structure made ofconductive material and formed on a contact substrate through aphotolithography process wherein the contact structure has a baseportion vertically formed on the contact substrate, a horizontalportion, one end of which being formed on the base portion, and acontact portion vertically formed on another end of the horizontalportion; a contact trace formed on the contact substrate andelectrically connected to the contact structure at one end, and an uppersurface of the other end of the contact trace is formed as a contactpad; a contact target provided on a printed circuit board (PCB)substrate or lead frame to be electrically connected with the contactpad of the contact trace through a conductive lead or wire; an elastomerprovided under the contact substrate for allowing flexibility in theinterconnection and packaging of the contact structure; and a supportstructure for supporting the contact structure, the contact substrateand the elastomer.

In another aspect of the present invention, a connector is provided toreceive the other end of the contact trace to establish electricalconnection therebetween. In a further aspect of the present invention, aconductive bump is provided between the other end of the contact traceand the PCB pad to establish electrical connection thereamong. In afurther aspect of the present invention, a conductive polymer isprovided between the other end of the contact trace and the PCB pad toestablish electrical connection thereamong.

In a further aspect of the present invention, the interconnection andpackaging of the contact structure is established through a bonding wirebetween the contact pad of the contact trace and a contact target. In afurther aspect of the present invention, the interconnection andpackaging of the contact structure is established through a single layerlead of tape automated bonding (TAB) structure extending between thecontact pad of the contact trace and a contact target. In a furtheraspect of the present invention, the interconnection and packaging ofthe contact structure is established through double layer leads of tapeautomated bonding (TAB) structure extending between the contact pad ofthe contact trace and a contact target. In a further aspect of thepresent invention, the interconnection and packaging of the contactstructure is established through triple layer leads of tape automatedbonding (TAB) structure extending between the contact pad of the contacttrace and a contact target.

According to the present invention, the packaging and interconnectionhas a very high frequency bandwidth to meet the test requirements in thenext generation semiconductor technology. The packaging andinterconnection is able to mount the contact structure on a probe cardor equivalent thereof by electrically connecting therewith through theupper surface of the contact structure. Moreover, because of therelatively small number of overall components to be assembled, theinterconnection and packaging of the present invention can be fabricatedwith low cost and high reliability as well as high productivity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a structural relationship betweena substrate handler and a semiconductor test system having a test head.

FIG. 2 is a schematic diagram showing an example of detailed structurefor connecting the test head of the semiconductor test system to thesubstrate handler.

FIG. 3 is a bottom view showing an example of the probe card having anepoxy ring for mounting a plurality of cantilevers as probe contactors.

FIGS. 4A-4E are circuit diagrams showing equivalent circuits of the becard of FIG. 3.

FIG. 5 is a schematic diagram showing contact structures associated withthe present invention produced through a photolithography process.

FIGS. 6A-6C are schematic diagrams showing examples of contact structureassociated with the present invention formed on a silicon substrate.

FIG. 7 is a schematic diagram showing a first embodiment of the presentinvention in which the packaging and interconnection is established by abonding wire between a contact pad provided at an upper surface of thecontact structure and a lead frame.

FIG. 8 a schematic diagram showing a modified structure of the firstembodiment of the present invention.

FIG. 9 is a schematic diagram showing a second embodiment of the presentinvention in which the packaging and interconnection is established by asingle layer TAB (tape automated bonding) between a contact pad providedat an upper surface of the contact structure and a contact target on aprobe card or package.

FIG. 10 is a schematic diagram showing a modified structure of thesecond embodiment of the present invention in which a straight TAB isincorporated as an interconnection and payckaging member.

FIG. 11 is a schematic diagram showing a further modified structure ofthe second embodiment of the present invention in which a contact targetis a connector.

FIG. 12 is a schematic diagram showing a further modified structure ofthe second embodiment of the present invention in which a conductivebump is incorporated between the TAB and the contact target as aninterconnection and packaging member.

FIG. 13 is a schematic diagram showing a further modified structure ofthe second embodiment of the present invention in which a conductivepolymer is incorporated between the TAB and the contact target as aninterconnection and packaging member.

FIG. 14 is a schematic diagram showing a third embodiment of the presentinvention in which the packaging and interconnection is established by adouble layer TAB (tape automated bonding) between a contact pad providedat an upper surface of the contact structure and a contact target on aprobe card or package.

FIG. 15 is a schematic diagram showing a modified structure of the thirdembodiment of the present invention in which a straight double layer TABis incorporated as an interconnection and packaging member to beconnected to a pair of contact targets.

FIG. 16 is a schematic diagram showing a further modified structure ofthe third embodiment of the present invention in which a contact targetis a connector to be connected with the double layer TAB.

FIG. 17 is a schematic diagram showing a further modified structure ofthe third embodiment of the present invention in which a contact targetis a connector to be connected with the straight double layer TAB.

FIG. 18 is a schematic diagram showing a further modified structure ofthe third embodiment of the present invention in which a conductive bumpis incorporated between the TAB and the contact target as aninterconnection and packaging member.

FIG. 19 is a schematic diagram showing a further modified structure ofthe third embodiment of the present invention in which a pair ofconductive bumps are incorporated between the double layer TAB and thecontact targets as interconnection and packaging members.

FIG. 20 is a schematic diagram showing a further modified structure ofthe third embodiment of the present invention in which a conductivepolymer is incorporated between the double layer TAB and the contacttarget as an interconnection and packaging member.

FIG. 21 is a schematic diagram showing a further modified structure ofthe third embodiment of the present invention in which a pair ofconductive polymer are incorporated between the double layer TAB and thecontact targets as interconnection and packaging members.

FIG. 22 is a schematic diagram showing a fourth embodiment of thepresent invention in which the packaging and interconnection isestablished by a triple layer TAB (tape automated bonding) between acontact pad provided at an upper surface of the contact structure and acontact target on a probe card or package.

FIG. 23 is a schematic diagram showing a modified structure of thefourth embodiment of the present invention in which a straight triplelayer TAB is incorporated as an interconnection and packaging member tobe connected to three contact targets.

FIG. 24 is a schematic diagram showing a further modified structure ofthe fourth embodiment of the present invention in which a contact targetis a connector to be connected with e triple layer TAB.

FIG. 25 is a schematic diagram showing a further modified structure ofthe fourth embodiment of the present invention in which a contact targetis a connector to be connected with the straight triple layer TAB.

FIG. 26 is a schematic diagram showing a further modified structure ofthe fourth embodiment of the present invention in which a conductivebump is incorporated between the TAB and the contact target as aninterconnection and packaging member

FIG. 27 is a schematic diagram showing a further modified structure ofthe fourth embodiment of the present invention in which three conductivebumps are incorporated between the triple layer TAB and the contacttargets as interconnection and packaging members.

FIG. 28 is a schematic diagram showing a further modified structure ofthe fourth embodiment of the present invention in which a conductivepolymer is incorporated between the triple layer TAB and the contacttarget as an interconnection and packaging member.

FIG. 29 is a schematic diagram showing a further modified structure ofthe fourth embodiment of the present invention in which three conductivepolymer are incorporated between the triple layer TAB and the contacttargets as interconnection and packaging members.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

To establish a packaging and interconnection of a contact structuredirectly with a probe card or indirectly with a probe card through an ICpackage, examples of FIGS. 6A-6C show basic three types of electricalpath extended from the contact structure to form such interconnections.FIG. 6A shows an example in which such an electrical connection isestablished at the top of the substrate. FIG. 6B shows an example inwhich an electrical connection is established at the bottom of thesubstrate while FIG. 6C shows an example in which an electricalconnection is formed at the edge of the substrate. Almost any types ofexisting IC package design or probe card design can accommodate at leastone of the interconnect types of FIGS. 6A-6C.

Each of FIGS. 6A-6C include a contact interconnect trace 32 alsodesignated by a which is to establish electrical connection with a probecard or any intermediate member to a probe card. The contact structure30 has vertical portions b and d and a horizontal beam c and a tipportion e. The tip portion e of the contact structure 30 is preferablysharpened to achieve a scrubbing effect when pressed against contacttargets 320 such as shown in FIG. 5. The spring force of the horizontalbeam c provides an appropriate contact force against the contact target320. An example of material of the contact structure 30 and the contacttrace 32 includes nickel, aluminum, copper and other conductivematerials. The inventors of this application have provided a detaileddescription of production process of the contact structure 30 and thecontact interconnect trace 32 on the silicon substrate 20 in the abovenoted U.S. application Ser. No. 09/099,614 now abandoned.

In the present invention, the packaging and interconnection of a contactstructure is directed to the type of structure having a contact trace atan upper surface thereof (top type contact trace) as shown in FIG. 6A.Various embodiments of the present invention on the top type packagingand interconnection will be described with reference to the drawings.

FIGS. 7 and 8 show a first embodiment of the present invention whereinthe top type contact trace is coupled to a lead frame provided, forexample, of a probe card (not shown) or an IC package (not shown)through a bonding wire. In the first example of FIG. 7, a contactstructure 30 formed on a contact substrate 20 is electrically connectedto a contact trace 32 which is the top type contact trace noted above.The contact trace 32 has, at its end, a contact pad 33, an upper surfaceof which is designed to establish an electrical connection with contacttargets through various contact means such as a bonding wire 72. Thewire 72 is a thin (15-25 μm) wire made, for example, of gold oraluminum.

Typically, the contact substrate 20 is a silicon substrate althoughother types of dielectric substrate, such as glass epoxy, polyimide,ceramic, and alumina substrates are also feasible. In the example ofFIG. 7, the bonding wire 72 connects the contact pad 33 and a lead frame45 of, for example, a probe card. The contact substrate 20 and the leadframe 45 are mounted on a support structure 52 through, for example, anadhesive (not shown).

Any wire bonding procedure can be used to establish the connecting bythe bonding wire 72. The wire 72 is first bonded to the contact pad 33of the contact trace and spanned to the lead frame 45. The wire 72 isbonded to the lead frame 45 and is clipped and the entire process isrepeated at the next bonding pad. The wire bonding is done with eithergold or aluminum wires. Both materials are highly conductive and ductileenough to withstand deformation during the bonding steps and stillremaining strong and reliable. In the gold wire bonding,thermo-compression (TC) and thermosonic methods are typically used. Inthe aluminum wire bonding, ultrasonic and wedge bonding methods aretypically used.

In the example of FIG. 8, the contact trace 32 is connected at its uppersurface with a printed circuit board (PCB) interconnect pad 38 providedon a PCB substrate 62. The PCB substrate 62 can be a probe card such asshown in FIG. 3 or an intermediate circuit component between the contactstructure and the probe card. The PCB substrate is mounted on a supportstructure 52. The contact substrate 20 and the support structure 52 arefixed with one another by, for example, an adhesive (not shown).Similarly, the PCB substrate and the support structure 52 are fixed withone another by an adhesive (not shown).

FIGS. 9-13 show a second embodiment of the present invention wherein thetop type contact trace is coupled to a contact target through a singlelayer lead formed by a tape automated bonding (TAB) process. In thefirst example of FIG. 9, the contact structure 30 formed on a contactsubstrate 20 is electrically connected to the contact pad 33 via thecontact trace 32. The contact pad 33 is connected at its upper surfacewith a TAB lead 74 which is also connected to a printed circuit board(PCB) interconnect pad 38 provided on a PCB substrate 62 ₂.

The contact substrate 20 is mounted on the PCB substrate 62 ₂ through anelastomer 42 and a support structure 52 ₂. The contact substrate 20, theelastomer 42, the support structure 52 ₂ and the PCB substrate 62 ₂ arefixed with one another by, for example, an adhesive (not shown). In thisexample, the TAB lead 74 for connecting the contact pad 33 and the PCBpad 38 has a gull-wing shape where a gull-wing portion A is bonded tothe PCB pad 38. A support member 54 is provided on the support structure52 ₂ to support the TAB lead 74.

The TAB lead 74 has a gull-wing shape which is similar to the standard“gull-wing lead” used in a surface mount technology. Because of thedown-ward bent of the gull-wing type TAB lead 74, a sufficient verticalclearance is achieved at the left end of FIG. 9 over the contact portionbetween the PCB pad 38 and the lead 74. The lead form of the TAB lead 74(downward bent, gull-wing lead) may require special tooling to producethe same. Since a large number of interconnection between the contacttrace and the PCB pad will be used in the application such assemiconductor testing, several hundred connections, such tooling may bestandardized for a multiple of contact traces with given pitch.

The electrical connections between the contact pad 33 and the TAB lead74 and between the TAB lead 74 and the PCB pad 38 will be established byvarious bonding technologies including thermosonic bonding,thermocompression bonding, and ultrasonic bonding technique. In anotheraspect, such electrical connections will be established through asurface mount technology (SMT) such as using a screen printable solderpaste. A soldering process is carried out based on the reflowcharacteristics of the solder paste and other solder materials wellknown in the art.

The PCB substrate 62 ₂ itself may be a probe card such as shown in FIG.3 or provided separately and mounted directly or indirectly on the probecard. In the former case, the PCB 62 ₂ may make direct contact with aninterface of a test system such as an IC tester in a manner shown inFIG. 2. In the latter case, the PCB substrate 62 ₂ is pinned or in useof a conductive polymer for establishing an electrical contact to thenext level of a contact mechanism on the probe card. Such types ofelectrical connection between the PCB substrate 62 ₂ and the probe cardthrough pins or conductive polymer would allow for field repairability.

The PCB substrate 62 ₂ may be a multiple layer structure which iscapable of providing high bandwidth signals, distributed high frequencycapacitance and integrated high frequency chip capacitors for powersupply decoupling as well as high pin counts (number of I/O pins andassociated signal paths). An example of material of the PCB 62 ₂ isstandard high performance glass epoxy resin. Another example of materialis ceramics which is expected to minimize mismatch in coefficient oftemperature expansion (CTE) rates during high temperature applicationsuch as a burn-in test of semiconductor wafers and packaged IC devices.

The support structure 52 ₂ is to establish a physical strength of thepackaging and interconnection of the contact structure. The supportstructure 52 ₂ is made of, for example, ceramic, molded plastic ormetal. The elastomer 42 is to establish flexibility in the packaging andinterconnection of the present invention to overcome a potentialplanarization mechanism. The elastomer 42 also functions to absorb amismatch in temperature expansion rates between the contact substrate 20and the PCB substrate 62 ₂.

An example of overall length of the contact trace 32 and the TAB lead 74is in the range from several ten micrometers to several hundredmicrometers. Because of the short path length, the packaginginterconnection of the present invention can be easily operable in ahigh frequency band such as several GHz or even higher. Moreover,because of a relatively small number of overall components to beassembled, the packaging and interconnection of the present inventioncan be fabricated with low cost and high reliability as well as highproductivity.

FIG. 10 shows another example of the second embodiment of the presentinvention. A TAB lead 74 ₂ is straight and connects the contact pad 33to the PCB pad 38 provided on a printed circuit board (PCB) substrate 62₃. To match the vertical position of the PCB pad 38, the PCB substrate62 ₃ has a raised portion at the left end thereof.

The electrical connection between the TAB lead 74 ₂ and the PCB pad 38will be established by a surface mount technology (SMT) such as using ascreen printable solder paste as well as various other bondingtechnologies including thermosonic bonding, thermocompression bonding,and ultrasonic bonding technique. Because of the significantly smallsizes of the components and signal path lengths involved in the contactstructure 30, contact trace 32, and the TAB lead 74 ₂, the example ofFIG. 10 can operate at a very high frequency band, such as several GHz.Moreover, because of the small number and simple structure of componentsto be assembled, the interconnection and packaging of the presentinvention can be fabricated with low cost and high reliability as wellas high productivity.

FIG. 11 shows a further modification of the second embodiment of thepresent invention wherein the top type contact trace 32 is coupled to aconnector provided on a printed circuit board or other structure. In theexample of FIG. 11, a contact pad 33 connected to the contact trace 32is connected to a connector 46 via a single layer TAB lead 74 ₃. Theconnector 46 is provided on a support structure 52 ₃. Typically, thecontact structure 30, contact trace 32 and the contact pad 33 are formedon the contact substrate 20 through photolithography processes. Thecontact substrate 20 is a silicon substrate although other types ofdielectric substrate, such as glass epoxy, polyimide, ceramic, andalumina substrates are also feasible.

In this example, the TAB lead 74 ₃ has a shape similar to the gull-wingwidely used in the surface mount technology and incorporated in theexample of FIG. 9. At about the center of FIG. 11, the contact substrate20 is mounted on the support structure 52 ₃ through an elastomer 42. Thecontact substrate 20, the elastomer 42 and the support structure 52 ₃are attached with one another by, for example, an adhesive (not shown).

The connector 46 may be mechanically fixed to the support structure 52 ₃through an attachment mechanism (not shown). The end of the TAB lead 74₃ is inserted in a receptacle (not shown) of the connector 46. As iswell known in the art, such a receptacle has a spring mechanism toprovide a sufficient contact force when receiving the end of the TABlead 74 ₃ therein. Between the TAB lead 74 ₃ and the support structure52 ₃, there is provided a support member 54 to support the TAB lead 74 ₃extending between the contact pad 33 and the connector 46. Also wellknown in the art, an inner surface of such a receptacle is provided withconductive metal such as gold, silver, palladium or nickel.

The connector 46 may be integrated with straight or right angle pins,which may be connected to the receptacle noted above, for directconnection to a printed circuit board (PCB). A PCB to mount theconnector 46 thereon can be either solid or flexible. As is known in theart, a flexible PCB is formed on a flexible base material and has flatcables therein. Alternatively, the connector 46 may be integrated with acoaxial cable assembly in which a receptacle is attached to an innerconductor of the coaxial cable for receiving the end of the TAB lead 74₃ therein. The connection between the connector 46 and the TAB lead 74 ₃or the support structure 52 ₃ is not a permanent attachment method,allowing for field replacement and repairability of the contact portion.

Typically, the contact substrate 20 is a silicon substrate althoughother types of substrate, such as glass epoxy, polyimide, ceramic, andalumina substrates are also feasible. The support structure 52 ₃ is toestablish a physical strength of the packaging and interconnection ofthe contact structure. The support structure 52 ₃ is made of, forexample, ceramic, molded plastic or metal. The elastomer 42 is toestablish flexibility in the interconnection and packaging of thepresent invention to overcome a potential planarization mechanism. Theelastomer 42 also functions to absorb a mismatch in temperatureexpansion rates between the contact substrate 20 and a PCB substrate tomount the connector 46 thereon.

An example of overall length of the contact trace 32 and the TAB lead 74₃ is in the range from several ten micrometers to several hundredmicrometers. Because of the short path length, the interconnection andpackaging of the present invention can be easily operable in a highfrequency band such as several GHz or even higher. Moreover, because ofthe lower total number of components to be assembled, the packaging andinterconnection of the present invention can be fabricated with low costand high reliability as well as high productivity. The gull-wing shapedTAB lead 74 ₃ may require special tooling in the production process,which may be standardized for a multiple of contact traces with a givenpitch.

FIG. 12 shows a further example of the second embodiment of the presentinvention wherein the top type contact trace is coupled to a padprovided on a printed circuit board through a conductive bump. In theexample of FIG. 12, a contact structure 30, a contact trace 32 and acontact tab 33 are formed on a contact substrate 20. Typically, thecontact substrate 20 is a silicon substrate although other types ofdielectric substrate, such as glass epoxy, polyimide, ceramic, andalumina substrates are also feasible. The contact trace 32 is connectedto a PCB (print circuit board) pad 38 provided on a PCB substrate 62 ₂through a conductive bump 56 via a TAB lead 74 ₄.

In this example, the TAB lead 74 ₄ has a shape similar to that shown inthe example of FIG. 11. The contact substrate 20 is mounted on the PCBsubstrate 62 ₂ through a support structure 52 ₂ and an elastomer 42. Thecontact substrate 20, the elastomer 42, the support structure 52 ₂, andthe PCB substrate 62 ₂ are attached with one another by, for example, anadhesive (not shown). Between the TAB lead 74 ₄ and the supportstructure 52 ₂, there is provided a support member 54 to support the TABlead 74 ₄ extending between the contact pad 33 and the PVB pad 38.

By the application of the heat, the conductive bump 56 is reflowed ontothe PCB pad 38 for attachment between the TAB lead 74 ₄ and the PCB pad38. An example of the conductive bump 56 is a solder bump used in astandard solder ball technology. Another example of the conductive bump56 is a fluxless solder ball used in a plasma-assisted dry solderingtechnology.

Further examples of the conductive bump 56 are a conductive polymer bumpand a compliant bump which involve the use of polymer in the bump. Thishelps in minimizing planarization problems or CTE (coefficient oftemperature expansion) mismatches in the packaging and interconnection.There is no reflowing of metal, which prevents bridging between contactpoints. The conductive polymer bump is made of a screen printableconductive adhesive. The compliant bump is a polymer core bump with ametal coating. The polymer is typically plated with gold and iselastically compressible. Still further example of the conductive bump56 is a bump used in a controlled collapse chip connection technology inwhich solder balls are formed by an evaporation process.

The PCB substrate 62 ₂ itself may be a probe card such as shown in FIG.3 or provided separately and mounted directly or indirectly on the probecard. In the former case, the PCB substrate 62 ₂ may make direct contactwith an interface of a test system such as an IC tester in the mannershown in FIG. 2. In the latter case, the PCB substrate 62 ₂ is pinned orin use of a conductive polymer for establishing an electrical contact tothe next level. Such types of electrical connection between the PCBsubstrate 62 ₂ and the probe card through pins or conductive polymerwould allow for field repairability.

The PCB substrate 62 ₂ may be a multiple layer structure which iscapable of providing high bandwidth signals, distributed high frequencycapacitance and integrated high frequency chip capacitors for powersupply decoupling as well as high pin counts (number of I/O pins andassociated signal paths). An example of material of the PCB substrate 62₂ is standard high performance glass epoxy resin. Another example of thematerial is ceramics which is expected to minimize mismatch incoefficient of temperature expansion (CTE) rates during high temperatureapplication such as a burn-in test of semiconductor wafers and packagedIC devices.

The support structure 52 ₂ is to establish a physical strength of thepackaging and interconnection of the contact structure. The supportstructure 52 ₂ is made of, for example, ceramic, molded plastic ormetal. The elastomer 42 is to establish flexibility in the packaging andinterconnection of the present invention to overcome a potentialplanarization mechanism. The elastomer 42 also functions to absorb amismatch in temperature expansion rates between the contact substrate 20and the PCB substrate 62 ₂.

An example of overall length of the contact trace 32 and the TAB lead 74₄ is in the range from several ten micrometers to several hundredmicrometers. Because of the short path length, the interconnection andpackaging of the present invention can be easily operable in a highfrequency band such as several GHz or even higher. Moreover, because ofthe lower total number of components to be assembled, the packaging andinterconnection of the present invention can be fabricated with low costand high reliability as well as high productivity.

FIG. 13 shows a further example of the second embodiment of the presentinvention wherein the top type contact trace is coupled to a padprovided on a printed circuit board through a conductive polymer. In theexample of FIG. 13, a contact structure 30, a contact trace 32, and acontact pad 33 are formed on a contact substrate 20. The contact pad 33is connected to a PCB (print circuit board) pad 38 provided on a PCBsubstrate 62 ₂ through a TAB lead 74 ₄ and a conductive polymer 66.Typically, the contact substrate 20 is a silicon substrate althoughother types of dielectric substrate, such as glass epoxy, polyimide,ceramic, and alumina substrates are also feasible.

In this example, the TAB lead 74 ₄ has a shape similar to that shown inthe example of FIGS. 11 and 12. The contact substrate 20 is mounted onthe PCB substrate 62 ₂ through a support structure 52 ₂ and an elastomer42. The contact substrate 20, the elastomer 42, the support structure 52₂, and the PCB substrate 62 ₂ are attached with one another by, forexample, an adhesive (not shown).

Most conductive polymers are designed to be conductive between themating electrodes normally in vertical of angled directions and notconductive in the horizontal direction. An example of the conductivepolymer 66 is a conductive elastomer which is filled with conductivewire that extends beyond the surface of the elastomer.

Various other examples of the conductive polymer 66 are possible such asan anisotropic conductive adhesive, anisotropic conductive film,anisotropic conductive paste, and anisotropic conductive particles. Theanisotropic conductive adhesive is filled with conductive particles thatdo not touch each other. The conductive path is formed by pressing theadhesive between the two electrodes at a specific location. Theanisotropic conductive film is a thin dielectric resin filled withconductive particles that do not touch each other. The conductive pathis formed by pressing the film between the two electrodes at a specificlocation.

The anisotropic conductive paste is a screen printable paste which isfilled with conductive particles that do not touch each other. Theconductive path is formed by pressing the paste between the twoelectrodes at a specific location. The anisotropic conductive particleis a thin dielectric resin filled with conductive particles coated witha very thin layer of dielectric material to improve isolation. Theconductive path is formed by pressing the particle with enough force toexplode the dielectric coating on the particles, between the twoelectrodes at a specific location.

The PCB substrate 62 ₂ itself may be a probe card such as shown in FIG.3 or provided separately and mounted directly or indirectly on the probecard. In the former case, the PCB substrate 62 ₂ may make direct contactwith an interface of a test system such as an IC tester in the mannershown in FIG. 2. In the latter case, the PCB substrate 62 ₂ is pinned orin use of a conductive polymer for establishing an electrical contact tothe next level. Such types of electrical connection between the PCBsubstrate 62 ₂ and the probe card through pins or conductive polymerwould allow for field repairability.

The PCB substrate 62 ₂ may be a multiple layer structure which iscapable of providing high bandwidth signals, distributed high frequencycapacitance and integrated high frequency chip capacitors for powersupply decoupling as well as high pin counts (number of I/O pins andassociated signal paths). An example of material of the PCB substrate 62₂ is standard high performance glass epoxy resin. Another example ofmaterial is ceramics which is expected to minimize mismatch incoefficient of temperature expansion (CTE) rates during high temperatureapplication such as a burn-in test of semiconductor wafers and packagedIC devices.

The support structure 52 ₂ is to establish a physical strength of thepackaging and interconnection of the contact structure. The supportstructure 52 ₂ is made of, for example, ceramic, molded plastic ormetal. The elastomer 42 is to establish flexibility in the packaging andinterconnection of the present invention to overcome a potentialplanarization mechanism. The elastomer 42 also functions to absorb amismatch in temperature expansion rates between the contact substrate 20and the PCB substrate 62 ₂.

An example of length of the contact trace 32 is from several tenmicrometers to several hundred micrometers. Because of the short pathlength, the packaging and interconnection of the present invention canbe easily operable in a high frequency band such as several GHz or evenhigher. Moreover, because of the lower total number of components to beassembled, the interconnection and packaging of the present inventioncan be fabricated with low cost and high reliability as well as highproductivity.

FIGS. 14-21 show a third embodiment of the present invention wherein thetop type contact trace is coupled to a contact target through a doublelayer lead formed by a tape automated bonding (TAB) process. In thefirst example of FIG. 14, the contact structure 30 formed on a contactsubstrate 20 is electrically connected to the contact pad 33 via thecontact trace 32. The contact pad 33 is connected at its upper surfacewith a TAB lead 76 which is also connected to a printed circuit board(PCB) interconnect pad 38 provided on a PCB substrate 62 ₂.

The contact substrate 20 is mounted on the PCB substrate 62 ₂ through anelastomer 42 ₂ and a support structure 52 ₄. The contact substrate 20,the elastomer 42 ₂, the support structure 52 ₄ and the PCB substrate 62₂ are fixed with one another by, for example, an adhesive (not shown).In this example, the double layered TAB lead 76 for connecting thecontact pad 33 and the PCB pad 38 has an upper lead A and a lower leadB. A support member 54 ₂ is provided between the upper lead and thelower lead of the TAB lead 76.

The TAB lead 76 has a gull-wing shape which is similar to the standard“gull-wing lead” used in a surface mount technology. Because of thedown-ward bent of the gull-wing type TAB lead 76, a sufficient verticalclearance is achieved at the left end of FIG. 14 over the contactportion between the PCB pad 38 and the lead 76. The lead form of the TABlead 76 (downward bent, gull-wing lead) may require special tooling toproduce the same. Since a large number of interconnection between thecontact trace and the PCB pad will be used in the application such assemiconductor testing, several hundred connections, such tooling may bestandardized for a multiple of contact traces with given pitch.

The structure of the TAB lead 76 having the tiered leads A and Bestablish a low resistance in a signal path because of two leads. Thisis useful in transmitting a large current such as in a ground line or apower line for testing a semiconductor device with high speed withoutdeforming the waveforms of test signals.

The electrical connections between the contact pad 33 and the TAB lead76 and between the TAB lead 76 and the PCB pad 38 will be established byvarious bonding technologies including thermosonic bonding,thermocompression bonding, and ultrasonic bonding technique. In anotheraspect, such electrical connections will be established through asurface mount technology (SMT) such as using a screen printable solderpaste. A soldering process is carried out based on the reflowcharacteristics of the solder paste and other solder materials wellknown in the art.

The PCB substrate 62 ₂ itself may be a probe card such as shown in FIG.3 or provided separately and mounted directly or indirectly on the probecard. In the former case, the PCB 62 ₂ may make direct contact with aninterface of a test system such as an IC tester in a manner shown inFIG. 2. In the latter case, the PCB substrate 62 ₂ is pinned or in useof a conductive polymer for establishing an electrical contact to thenext level of a contact mechanism on the probe card. Such types ofelectrical connection between the PCB substrate 62 ₂ and the probe cardthrough pins or conductive polymer would allow for field repairability.

The PCB substrate 62 ₂ may be a multiple layer structure which iscapable of providing high bandwidth signals, distributed high frequencycapacitance and integrated high frequency chip capacitors for powersupply decoupling as well as high pin counts (number of I/O pins andassociated signal paths). An example of material of the PCB 62 ₂ isstandard high performance glass epoxy resin. Another example of materialis ceramics which is expected to minimize mismatch in coefficient oftemperature expansion (CTE) rates during high temperature applicationsuch as a burn-in test of semiconductor wafers and packaged IC devices.

The support structure 52 ₄ is to establish a physical strength of thepackaging and interconnection of the contact structure. The supportstructure 52 ₄ is made of, for example, ceramic, molded plastic ormetal. The elastomer 42 ₂ is to establish flexibility in the packagingand interconnection of the present invention to overcome a potentialplanarization mechanism. The elastomer 42 ₂ also functions to absorb amismatch in temperature expansion rates between the contact substrate 20and the PCB substrate 62 ₂.

An example of overall length of the contact trace 32 and the TAB lead 76is in the range from several ten micrometers to several hundredmicrometers. Because of the short path length, the packaginginterconnection of the present invention can be easily operable in ahigh frequency band such as several GHz or even higher. Moreover,because of a relatively small number of overall components to beassembled, the packaging and interconnection of the present inventioncan be fabricated with low cost and high reliability as well as highproductivity.

FIG. 15 shows another example of the third embodiment of the presentinvention. In this example, a double layered TAB lead 76 ₂ having upperand lower leads A and B is provided to the contact pad 33 connected tothe contact structure 30. The upper lead A is provided in an upper andouter position of FIG. 15 than the lower lead B. The upper lead isconnected to a PCB pad 38 and the lower lead B is connected to a PCB pad39. To accommodate the PCB pads 38 and 39 thereon, a PCB substrate 62 ₄is arranged to have an edge having a larger thickness, i.e., a step, tomount the PCB pad 38, and an inner portion adjacent to the edge portionhaving a smaller thickness to mount the PCB pad 39.

The electrical connection between the TAB lead 76 ₂ and the PCB pads 38and 39 will be established by a surface mount technology (SMT) such asusing a screen printable solder paste as well as various other bondingtechnologies including thermosonic bonding, thermocompression bonding,and ultrasonic bonding technique. Because of the significantly smallsizes of the components and signal path lengths involved in the contactstructure 30, contact trace 32, and the TAB lead 76 ₂, the example ofFIG. 15 can operate at a very high frequency band, such as several GHz.Moreover, because of the small number and simple structure of componentsto be assembled, the interconnection and packaging of the presentinvention can be fabricated with low cost and high reliability as wellas high productivity.

The structure of the TAB lead 76 ₂ having the double layered leads A andB establish a fan out in the vertical dimension. This is useful indistributing a signal or power to two or more paths. Another advantageof the fan out is to increase the number of contact pads, i.e., todecrease the effective pitch (distance) between the contact pads.

FIG. 16 shows a further modification of the third embodiment of thepresent invention wherein the top type contact trace 32 is coupled to aconnector provided on a printed circuit board or other structure. In theexample of FIG. 16, a contact pad 33 connected to the contact trace 32is connected to a connector 46 via a double layer TAB lead 76 ₄. Theconnector 46 is provided on a support structure 52 ₅. Typically, thecontact structure 30, contact trace 32 and the contact pad 33 are formedon the contact substrate 20 through photolithography processes. Thecontact substrate 20 is a silicon substrate although other types ofdielectric substrate, such as glass epoxy, polyimide, ceramic, andalumina substrates are also feasible.

The connector 46 may be mechanically fixed to the support structure 52 ₅through an attachment mechanism (not shown). The end of the TAB lead 76₄ is inserted in a receptacle (not shown) of the connector 46. As iswell known in the art, such a receptacle has a spring mechanism toprovide a sufficient contact force when receiving the end of the TABlead 76 ₄ therein. Between the upper lead A and the lower lead B of thedouble layer TAB lead 76 ₄, there is provided a support member 54 ₂ tosupport the leads A and B of the TAB lead 76 ₄ extending between thecontact pad 33 and the connector 46. Also well known in the art, aninner surface of such receptacles are provided with conductive metalsuch as gold, silver, palladium or nickel.

The structure of the TAB lead 76 ₄ having the tiered leads A and Bestablish a low resistance in a signal path because of the two leads.This is useful in transmitting a large current such as in a ground lineor a power line for testing a semiconductor device with high speedwithout deforming the waveforms of the test signals.

The connector 46 may be integrated with straight or right angle pins,which may be connected to the receptacle noted above, for directconnection to a printed circuit board (PCB). A PCB to mount theconnector 46 thereon can be either solid or flexible. As is known in theart, a flexible PCB is formed on a flexible base material and has flatcables therein. Alternatively, the connector 46 may be integrated with acoaxial cable assembly in which a receptacle is attached to an innerconductor of the coaxial cable for receiving the ends of the TAB lead 76₄ therein. The connection between the connector 46 and the TAB lead 76 ₄or the support structure 52 ₅ is not a permanent attachment method,allowing for field replacement and repairability of the contact portion.

Typically, the contact substrate 20 is a silicon substrate althoughother types of substrate, such as glass epoxy, polyimide, ceramic, andalumina substrates are also feasible. The support structure 52 ₅ is toestablish a physical strength of the packaging and interconnection ofthe contact structure. The support structure 52 ₅ is made of, forexample, ceramic, molded plastic or metal. The elastomer 42 ₂ is toestablish flexibility in the interconnection and packaging of thepresent invention to overcome a potential planarization mechanism. Theelastomer 42 ₂ also functions to absorb a mismatch in temperatureexpansion rates between the contact substrate 20 and a PCB substrate tomount the connector 46 thereon.

FIG. 17 shows a further modification of the third embodiment of thepresent invention wherein the top type contact trace 32 is coupled to aconnector provided on a printed circuit board or other structure. In theexample of FIG. 17, a contact pad 33 connected to the contact trace 32is connected to a connector 46 ₂ via a double layer TAB lead 76 ₆. Thedouble layer TAB 76 ₆ has an upper lead A and a lower lead B each ofwhich is separated at the end. The connector 46 ₂ is provided on asupport structure 52 ₅.

The connector 46 ₂ may be mechanically fixed to the support structure 52₅ through an attachment mechanism (not shown). The ends of the leads Aand B of the TAB lead 76 ₆ are inserted in receptacles (not shown) ofthe connector 46 ₂. As is well known in the art, such a receptacle has aspring mechanism to provide a sufficient contact force when receivingthe end of the TAB lead 76 ₆ therein. Between the upper lead A and thelower lead B of the double layer TAB lead 76 ₆, there is provided asupport member 54 ₄ to support the leads A and B.

The structure of the TAB lead 76 ₆ having the double layered leads A andB establish a fan out in the vertical dimension. This is useful indistributing a signal or power to two or more paths. Another advantageof the fan out is to increase the number of contact pads, i.e., todecrease the effective pitch (distance) between the contact pads.

FIG. 18 shows a further example of the third embodiment of the presentinvention wherein the top type contact trace is coupled to a padprovided on a printed circuit board through a conductive bump. In theexample of FIG. 18, a contact structure 30, a contact trace 32 and acontact tab 33 are formed on a contact substrate 20. Typically, thecontact substrate 20 is a silicon substrate although other types ofdielectric substrate, such as glass epoxy, polyimide, ceramic, andalumina substrates are also feasible. The contact trace 32 is connectedto a PCB (print circuit board) pad 38 provided on a PCB substrate 62 ₂through a conductive bump 56 via a double layer TAB lead 76 ₄.

The contact substrate 20 is mounted on the PCB substrate 62 ₂ through asupport structure 52 ₄ and an elastomer 42 ₂. The contact substrate 20,the elastomer 42 ₂, the support structure 52 ₄, and the PCB substrate 62₂ are attached with one another by, for example, an adhesive (notshown). Between the upper lead A and the lower lead B of the TAB lead 76₄, there is provided with a support member 54 ₂ to support the upper andlower leads A and B.

By the application of the heat, the conductive bump 56 is reflowed ontothe PCB pad 38 for attachment between the TAB lead 76 ₄ and the PCB pad38. An example of the conductive bump 56 is a solder bump used in astandard solder ball technology. Another example of the conductive bump56 is a fluxless solder ball used in a plasma-assisted dry solderingtechnology.

Further examples of the conductive bump 56 are a conductive polymer bumpand a compliant bump which involve the use of polymer in the bump. Thishelps in minimizing planarization problems or CTE (coefficient oftemperature expansion) mismatches in the packaging and interconnection.There is no reflowing of metal, which prevents bridging between contactpoints. The conductive polymer bump is made of a screen printableconductive adhesive. The compliant bump is a polymer core bump with ametal coating. The polymer is typically plated with gold and iselastically compressible. Still further example of the conductive bump56 is a bump used in a controlled collapse chip connection technology inwhich solder balls are formed by an evaporation process.

The structure of the TAB lead 76 ₄ having the tiered leads A and Bestablish a low resistance in a signal path because of the two leads.This is useful in transmitting a large current such as in a ground lineor a power line for testing a semiconductor device with high speedwithout deforming the waveforms of the test signals.

FIG. 19 shows another example of the third embodiment of the presentinvention. In this example, a double layered TAB lead 76 ₂ having upperand lower leads A and B are provided to the contact pad 33 connected tothe contact structure 30. The upper lead A is provided in an upper andouter position than the lower lead B in FIG. 19. The upper lead isconnected to a PCB pad 38 via a conductive dump 56 and the lower lead Bis connected to a PCB pad 39 via a conductive dump 57. To accommodatethe PCB pads 38 and 39 thereon, a PCB substrate 62 ₄ is arranged to havean edge having a larger thickness, i.e., a step, to mount the PCB pad38, and an inner portion adjacent to the edge portion having a smallerthickness to mount the PCB pad 39.

By the application of the heat, the conductive bumps 56 and 57 arereflowed onto the PCB pads 38 and 39 for attachment between the TAB lead76 ₂ and the PCB pads 38 and 39. An example of the conductive bumps 56and 57 is a solder bump used in a standard solder ball technology.Another example of the conductive bumps 56 and 57 is a fluxless solderball used in a plasma-assisted dry soldering technology.

The structure of the TAB lead 76 ₂ having the double layered leads A andB establish a fan out in the vertical dimension. This is useful indistributing a signal or power to two or more paths. Another advantageof the fan out is to increase the number of contact pads, i.e., todecrease the effective pitch (distance) between the contact pads.

FIG. 20 shows a further example of the third embodiment of the presentinvention wherein the top type contact trace is coupled to a padprovided on a printed circuit board through a conductive polymer. In theexample of FIG. 20, a contact structure 30, a contact trace 32 and acontact tab 33 are formed on a contact substrate 20. Typically, thecontact substrate 20 is a silicon substrate although other types ofdielectric substrate, such as glass epoxy, polyimide, ceramic, andalumina substrates are also feasible. The contact trace 32 is connectedto a PCB (print circuit board) pad 38 provided on a PCB substrate 62 ₂through a conductive polymer 66 via a double layer TAB lead 76 ₄.

The contact substrate 20 is mounted on the PCB substrate 62 ₂ through asupport structure 52 ₄ and an elastomer 42 ₂. The contact substrate 20,the elastomer 42 ₂, the support structure 52 ₄, and the PCB substrate 62₂ are attached with one another by, for example, an adhesive (notshown). Between the upper lead A and the lower lead B of the TAB lead 76₄, there is provided with a support member 54 ₂ to support the upper andlower leads A and B.

Most conductive polymers are designed to be conductive between themating electrodes normally in vertical of angled directions and notconductive in the horizontal direction. An example of the conductivepolymer 66 is a conductive elastomer which is filled with conductivewire that extends beyond the surface of the elastomer.

Various other examples of the conductive polymer 66 are possible such asan anisotropic conductive adhesive, anisotropic conductive film,anisotropic conductive paste, and anisotropic conductive particles. Theanisotropic conductive adhesive is filled with conductive particles thatdo not touch each other. The conductive path is formed by pressing theadhesive between the two electrodes at a specific location. Theanisotropic conductive film is a thin dielectric resin filled withconductive particles that do not touch each other. The conductive pathis formed by pressing the film between the two electrodes at a specificlocation.

The anisotropic conductive paste is a screen printable paste which isfilled with conductive particles that do not touch each other. Theconductive path is formed by pressing the paste between the twoelectrodes at a specific location. The anisotropic conductive particleis a thin dielectric resin filled with conductive particles coated witha very thin layer of dielectric material to improve isolation. Theconductive path is formed by pressing the particle with enough force toexplode the dielectric coating on the particles, between the twoelectrodes at a specific location.

The structure of the TAB lead 76 ₄ having the tiered leads A and Bestablish a low resistance in a signal path because of the two leads.This is useful in transmitting a large current such as in a ground lineor a power line for testing a semiconductor device with high speedwithout deforming the waveforms of the test signals.

FIG. 21 shows another example of the third embodiment of the presentinvention. In this example, a double layered TAB lead 76 ₂ having upperand lower leads A and B are provided to the contact pad 33 connected tothe contact trace 32 and contact structure 30. The upper lead A isprovided in an upper and outer position than the lower lead B in FIG.21. The upper lead is connected to a PCB pad 38 via a conductive polymer66 and the lower lead B is connected to a PCB pad 39 via a conductivepolymer 67. To accommodate the PCB pads 38 and 39 thereon, a PCBsubstrate 62 ₄ is arranged to have an edge having a larger thickness,i.e., a step, to mount the PCB pad 38, and an inner portion adjacent tothe edge portion having a smaller thickness to mount the PCB pad 39.

The electrical connection between the TAB lead 76 ₂ and the PCB pads 38and 39 will be established by a surface mount technology (SMT) such asusing a screen printable solder paste as well as various other bondingtechnologies including thermosonic bonding, thermocompression bonding,and ultrasonic bonding technique.

The structure of the TAB lead 76 ₂ having the double layered leads A andB establish a fan out in the vertical dimension. This is useful indistributing a signal or power to two or more paths. Another advantageof the fan out is to increase the number of contact pads, i.e., todecrease the effective pitch (distance) between the contact pads.

FIGS. 22-29 show a fourth embodiment of the present invention whereinthe top type contact trace is coupled to a contact target through atriple layer lead formed by a tape automated bonding (TAB) process. Inthe first example of FIG. 22, the contact structure 30 formed on acontact substrate 20 is electrically connected to the contact pad 33 viathe contact trace 32. The contact pad 33 is connected at its uppersurface with a TAB lead 78 which is also connected to a printed circuitboard (PCB) interconnect pad 38 provided on a PCB substrate 62 ₂.

The contact substrate 20 is mounted on the PCB substrate 62 ₂ through anelastomer 42 and a support structure 52 ₆. The contact substrate 20, theelastomer 42, the support structure 52 ₆ and the PCB substrate 62 ₂ arefixed with one another by, for example, an adhesive (not shown). In thisexample, the triple layered TAB lead 78 for connecting the contact pad33 and the PCB pad 38 has an upper lead A, intermediate lead B and alower lead C. A support member 59 ₂ is provided between the upper lead Aand the intermediate lead B of the triple layered TAB lead 78. A supportmember 59 ₂ is provided between the intermediate lead B and the lowerlead C of the triple layered TAB lead 78.

The TAB lead 78 as a whole has a gull-wing shape which is similar to thestandard “gull-wing lead” used in a surface mount technology. Because ofthe down-ward bent of the gull-wing type TAB lead 78, a sufficientvertical clearance is achieved at the left end of FIG. 22 over thecontact portion between the PCB pad 38 and the TAB lead 78. The leadform of the TAB lead 78 (downward bent, gull-wing lead) may requirespecial tooling to produce the same. Since a large number ofinterconnection between the contact trace and the PCB pad will be usedin the application such as semiconductor testing, several hundredconnections, such tooling may be standardized for a multiple of contacttraces with given pitch.

The structure of the TAB lead 78 having the tiered leads A, B and Cestablish a low resistance and a large current capacity in a signal pathbecause of the three conductive leads. This is useful in transmitting alarge current such as in a ground line or a power line for testing asemiconductor device with high speed without deforming the waveforms oftest signals.

FIG. 23 shows another example of the fourth embodiment of the presentinvention. In this example, a triple layered TAB lead 78 ₂ having upper,intermediate and lower leads A, B and C is provided to the contact pad33 connected to the contact trace 32 and contact structure 30. The upperlead A is provided in an upper and outer position of FIG. 23 than theintermediate lead B. The intermediate lead B is provided in an upper andouter position of FIG. 23 than the lower lead C. The upper lead A isconnected to a PCB pad 38, the intermediate lead B is connected to a PCBpad 39, and the lower lead C is connected to a PCB pad 40. Toaccommodate the PCB pads 38, 39 and 40 thereon, a PCB substrate 62 ₆ isarranged to have steps to mount the PCB pads 38, 39 and 40 withdifferent vertical positions. A support member 54 ₅ is provided betweenthe upper lead A and the intermediate lead B and a support member 54 ₆is provided between the intermediate lead B and the lower lead C.

The electrical connection between the TAB lead 78 ₂ and the PCB pads 38,39 and 40 will be established by a surface mount technology (SMT) suchas using a screen printable solder paste as well as various otherbonding technologies including thermosonic bonding, thermocompressionbonding, and ultrasonic bonding technique. Because of the significantlysmall sizes of the components and signal path lengths involved in thecontact structure 30, contact trace 32, and the TAB lead 78 ₂, theexample of FIG. 23 can operate at a very high frequency band, such asseveral GHz. Moreover, because of the small number and simple structureof components to be assembled, the interconnection and packaging of thepresent invention can be fabricated with low cost and high reliabilityas well as high productivity.

The structure of the TAB lead 78 ₂ having the triple layered leads A, Band C establish a fan out in the vertical dimension. This is useful indistributing a signal or power to two or more paths. Another advantageof the fan out is to increase the number of contact pads, i.e., todecrease the effective pitch (distance) between the contact pads.

FIG. 24 shows a further modification of the fourth embodiment of thepresent invention wherein the top type contact trace 32 is coupled to aconnector provided on a printed circuit board or other structure. In theexample of FIG. 24, a contact pad 33 connected to the contact trace 32is connected to a connector 46 ₃ via a triple layer TAB lead 78 whichhas the same shape as that shown in FIG. 22. The connector 46 ₃ isprovided on a support structure 52 ₅.

The connector 46 ₃ may be mechanically fixed to the support structure 52₅ through an attachment mechanism (not shown). The end of the TAB lead78 is inserted in a receptacle (not shown) of the connector 46 ₃. As iswell known in the art, such a receptacle has a spring mechanism toprovide a sufficient contact force when receiving the end of the TABlead 78 therein. Between the upper lead A and the intermediate lead B ofthe triple layer TAB lead 78, there is provided a support member 59 ₁ tosupport the leads A and B. Between the intermediate lead B and the lowerlead C of the double layer TAB lead 78, there is provided a supportmember 59 ₂ to support the leads B and C.

The structure of the TAB lead 78 having the tiered leads A, B and Cestablish a low resistance and a large current capacity in a signal pathbecause of the three conductive leads. This is useful in transmitting alarge current such as in a ground line or a power line for testing asemiconductor device with high speed without deforming the waveforms oftest signals.

FIG. 25 shows a further modification of the third embodiment of thepresent invention wherein the top type contact trace 32 is coupled to aconnector provided on a printed circuit board or other structure. In theexample of FIG. 25, a contact pad 33 connected to the contact trace 32is connected to a connector 46 ₄ via a triple layer TAB lead 78 ₄. Thetriple layer TAB 78 ₄ has an upper lead A, an intermediate lead B and alower lead C each of which is separated at the end. The connector 46 ₄is provided on a support structure 52 ₆.

The connector 46 ₄ may be mechanically fixed to the support structure 52₆ through an attachment mechanism (not shown). The ends of the leads A,B and C of the TAB lead 78 ₄ are inserted in receptacles (not shown) ofthe connector 46 ₄. As is well known in the art, such a receptacle has aspring mechanism to provide a sufficient contact force when receivingthe end of the TAB lead 78 ₄ therein. A support member 59 ₃ is providedbetween the upper lead A and the intermediate lead B and a supportmember 59 ₄ is provided between the intermediate lead B and the lowerlead C of the triple TAB lead 78 ₄.

The structure of the TAB lead 78 ₄ having the triple layered leads A, Band C establish a fan out in the vertical dimension. This is useful indistributing a signal or power to two or more paths. Another advantageof the fan out is to increase the number of contact pads, i.e., todecrease the effective pitch (distance) between the contact pads.

FIGS. 26 shows a further example of the fourth embodiment of the presentinvention wherein the top type contact trace is coupled to a padprovided on a printed circuit board through a conductive bump. In theexample of FIG. 26, a contact structure 30, a contact trace 32 and acontact tab 33 are formed on a contact substrate 20. Typically, thecontact substrate 20 is a silicon substrate although other types ofdielectric substrate, such as glass epoxy, polyimide, ceramic, andalumina substrates are also feasible. The contact pad 33 is connected toa PCB (print circuit board) pad 38 provided on a PCB substrate 62 ₂through a conductive bump 56 via a triple layer TAB lead 78.

The contact substrate 20 is mounted on the PCB substrate 62 ₂ through asupport structure 52 ₆ and an elastomer 42. The contact substrate 20,the elastomer 42, the support structure 52 ₆, and the PCB substrate 62 ₂are attached with one another by, for example, an adhesive (not shown).Between the upper lead A and the intermediate lead B of the triple layerTAB lead 78, there is provided a support member 59 ₁ to support theleads A and B. Between the intermediate lead B and the lower lead C ofthe triple layer TAB lead 78, there is provided a support member 59 ₂ tosupport the leads B and C.

The structure of the TAB lead 78 having the tiered leads A, B and Cestablish a low resistance and a large current capacity in a signal pathbecause of the three conductive leads. This is useful in transmitting alarge current such as in a ground line or a power line for testing asemiconductor device with high speed without deforming the waveforms oftest signals.

By the application of the heat, the conductive bump 56 is reflowed ontothe PCB pad 38 for attachment between the TAB lead 78 and the PCB pad38. An example of the conductive bump 56 is a solder bump used in astandard solder ball technology. Another example of the conductive bump56 is a fluxless solder ball used in a plasma-assisted dry solderingtechnology.

FIG. 27 shows another example of the fourth embodiment of the presentinvention. In this example, a triple layered TAB lead 78 ₂ having upper,intermediate and lower leads A, B and C is provided to the contact pad33 connected to the contact structure 30. The upper lead A is providedin an upper and outer position of FIG. 27 than the intermediate lead B.The intermediate lead B is provided in an upper and outer position thanthe lower lead C in FIG. 27. The upper lead A is connected to a PCB pad38 through a conductive bump 56, the intermediate lead B is connected toa PCB pad 39 through a conductive bump 57, and the lower lead C isconnected to a PCB pad 40 through a conductive bump 58. To accommodatethe PCB pads 38, 39 and 40 thereon, a PCB substrate 62 ₆ is arranged tohave steps to mount the PCB pads 38, 39 and 40 with different verticalpositions. A support member 54 ₅ is provided between the upper lead Aand the intermediate lead B and a support member 54 ₆ is providedbetween the intermediate lead B and the lower lead C.

By the application of the heat, the conductive bumps 56, 57 and 58 arereflowed onto the PCB pads 38, 39 and 40 for attachment between the TABlead 78 ₂ and the PCB pads 38, 39 and 40. An example of the conductivebumps 56, 57 and 58 is a solder bump used in a standard solder balltechnology. Another example of the conductive bumps 56, 57 and 58 is afluxless solder ball used in a plasma-assisted dry soldering technology.

The structure of the TAB lead 78 ₂ having the triple layered leads A, Band C establish a fan out in the vertical dimension. This is useful indistributing a signal or power to two or more paths. Another advantageof the fan out is to increase the number of contact pads, i.e., todecrease the effective pitch (distance) between the contact pads.

FIGS. 28 shows a further example of the fourth embodiment of the presentinvention wherein the top type contact trace is coupled to a padprovided on a printed circuit board through a conductive polymer. In theexample of FIG. 28, a contact structure 30, a contact trace 32 and acontact tab 33 are formed on a contact substrate 20. Typically, thecontact substrate 20 is a silicon substrate although other types ofdielectric substrate, such as glass epoxy, polyimide, ceramic, andalumina substrates are also feasible. The contact pad 33 is connected toa PCB (print circuit board) pad 38 provided on a PCB substrate 62 ₂through a conductive polymer 66 via a triple layer TAB lead 78.

The contact substrate 20 is mounted on the PCB substrate 62 ₂ through asupport structure 52 ₆ and an elastomer 42. The contact substrate 20,the elastomer 42, the support structure 52 ₆, and the PCB substrate 62 ₂are attached with one another by, for example, an adhesive (not shown).Between the upper lead A and the intermediate lead B of the triple layerTAB lead 78, there is provided a support member 59 ₁ to support theleads A and B. Between the intermediate lead B and the lower lead C ofthe triple layer TAB lead 78, there is provided a support member 59 ₂ tosupport the leads B and C.

Most conductive polymers are designed to be conductive between themating electrodes normally in vertical of angled directions and notconductive in the horizontal direction. An example of the conductivepolymer 66 is a conductive elastomer which is filled with conductivewire that extends beyond the surface of the elastomer.

Various other examples of the conductive polymer 66 are possible such asan anisotropic conductive adhesive, anisotropic conductive film,anisotropic conductive paste, and anisotropic conductive particles. Theanisotropic conductive adhesive is filled with conductive particles thatdo not touch each other. The conductive path is formed by pressing theadhesive between the two electrodes at a specific location. Theanisotropic conductive film is a thin dielectric resin filled withconductive particles that do not touch each other. The conductive pathis formed by pressing the film between the two electrodes at a specificlocation.

The anisotropic conductive paste is a screen printable paste which isfilled with conductive particles that do not touch each other. Theconductive path is formed by pressing the paste between the twoelectrodes at a specific location. The anisotropic conductive particleis a thin dielectric resin filled with conductive particles coated witha very thin layer of dielectric material to improve isolation. Theconductive path is formed by pressing the particle with enough force toexplode the dielectric coating on the particles, between the twoelectrodes at a specific location.

The structure of the TAB lead 78 having the tiered leads A, B and Cestablish a low resistance and a large current capacity in a signal pathbecause of the three conductive leads. This is useful in transmitting alarge current such as in a ground line or a power line for testing asemiconductor device with high speed without deforming the waveforms oftest signals.

FIG. 29 shows another example of the fourth embodiment of the presentinvention. In this example, a triple layered TAB lead 78 ₂ having upper,intermediate and lower leads A, B and C is provided to the contact pad33 connected to the contact trace 32 and contact structure 30. The upperlead A is provided in an upper and outer position than the intermediatelead B in FIG. 29. The intermediate lead B is provided in an upper andouter position of FIG. 29 than the lower lead C. The upper lead A isconnected to a PCB pad 38 through a conductive polymer 66, theintermediate lead B is connected to a PCB pad 39 through a conductivepolymer 67, and the lower lead C is connected to a PCB pad 40 through aconductive polymer 68. To accommodate the PCB pads 38, 39 and 40thereon, a PCB substrate 62 ₆ is arranged to have steps to mount the PCBpads 38, 39 and 40 with different vertical positions. A support member545 is provided between the upper lead A and the intermediate lead B anda support member 546 is provided between the intermediate lead B and thelower lead C.

The structure of the TAB lead 78 ₂ having the triple layered leads A, Band C establish a fan out in the vertical dimension. This is useful indistributing a signal or power to two or more paths. Another advantageof the fan out is to increase the number of contact pads, i.e., todecrease the effective pitch (distance) between the contact pads.

According to the present invention, the packaging and interconnectionhas a very high frequency bandwidth to meet the test requirements in thenext generation semiconductor technology. The packaging andinterconnection is able to mount the contact structure on a probe cardor equivalent thereof by electrically connecting therewith through theupper surface of the contact structure. Moreover, because of arelatively small number of overall components to be assembled, theinterconnection and packaging of the present invention can be fabricatedwith low cost and high reliability as well as high productivity.

Although only a preferred embodiment is specifically illustrated anddescribed herein, it will be appreciated that many modifications andvariations of the present invention are possible in light of the aboveteachings and within the purview of the appended claims withoutdeparting the spirit and intended scope of the invention.

What is claimed is:
 1. A packaging and interconnection of a contactstructure, comprising: a contact structure made of conductive materialand formed on a contact substrate through a photolithography process,said contact structure having a base portion vertically formed on saidcontact substrate, a horizontal portion, one end of which being formedon said base portion, and a contact portion vertically formed on anotherend of said horizontal portion; a contact trace formed on said contactsubstrate and electrically connected to said contact structure at oneend, the other end of said contact trace being formed of a contact pad;a connection target provided at an outer periphery of said contact traceto be electrically connected with said contact pad; a bonding wire forelectrically connecting an upper surface of the contact pad and thecontact target; an elastomer provided under said contact substrate forallowing flexibility in said interconnection and packaging; and asupport structure provided under said elastomer for supporting saidcontact structure, said contact substrate and said elastomer; whereinsubstantially all portions of said contact structure are projected fromsaid contact substrate to a free space to allow free movements of atleast said horizontal portion and said contact portion, and wherein saidhorizontal portion of said contact structure produces a contact forcewhen said contact structure is pressed against a contact target, therebyachieving a scrubbing effect on a surface of the contact target.
 2. Apackaging and interconnection of a contact structure as defined in claim1, wherein said contact substrate is a silicon substrate on which saidcontact structure is directly formed through said photolithographyprocess.
 3. A packaging and interconnection of a contact structure asdefined in claim 1, wherein said contact substrate is a dielectricsubstrate on which said contact structure is directly formed throughsaid photolithography process.
 4. A packaging and interconnection of acotact structure as defined in claim 1, wherein said connection targetis provided on a printed circuit board (PCB) substrate.
 5. A packagingand interconnection of a contact structure, comprising: a contactstructure made of conductive material and formed on a contact substratethrough a photolithography process, said contact structure having a baseportion vertically formed on said contact substrate, a horizontalportion, one end of which being formed on said base portion, and acontact portion vertically formed on another end of said horizontalportion; a contact trace formed on said contact substrate andelectrically connected to said contact structure at one end, the otherend of said contact trace being formed of a contact pad; a printedcircuit board (PCB) pad provided on a printed circuit board (PCB)substrate positioned at an outer periphery of said contact structure tobe electrically connected with said contact pad; a single layer lead forelectrically connecting an upper surface of the contact pad and the PCBpad; an elastomer provided under said contact substrate for allowingflexibility in said interconnection and packaging; and a supportstructure provided between said elastomer and said PCB substrate forsupporting said contact structure, said contact substrate and saidelastomer; wherein substantially all portions of said contact structureare projected from said contact substrate to a free space to allow freemovements of at least said horizontal portion and said contact portion,and wherein said horizontal portion of said contact structure produces acontact force when said contact structure is pressed against a contacttarget, thereby achieving a scrubbing effect on a surface of the contacttarget.
 6. A packaging and interconnection of a contact structure asdefined in claim 5, wherein said PCB substrate is made of glass epoxyresin or ceramics.
 7. A packaging and interconnection of a contactstructure as defined in claim 5, wherein said PCB substrate is amultilayer printed circuit board.
 8. A packaging and interconnection ofa contact structure as defined in claim 5, wherein said supportstructure is made of ceramic, molded plastic or metal.
 9. A packagingand interconnection of a contact structure as defined in claim 5,wherein said single layer lead is formed in a tape automated bonding(TAB) structure to be used in the packaging and interconnection.
 10. Apackaging and interconnection of a contact structure as defined in claim5, wherein said single layer lead has a gull-wing shape for electricallyconnecting said contact pad and said PCB pad.
 11. A packaging andinterconnection of a contact structure as defined in claim 5, whereinone end of said single layer lead is connected to said PCB pad through aconductive bump.
 12. A packaging and interconnection of a contactstructure as defined in claim 11, wherein said conductive bump is asolder ball which reflows by application of heat to electrically connectsaid other end of said single layer lead and said PCB pad.
 13. Apackaging and interconnection of a contact structure as defined in claim11, wherein said conductive bump is a conductive polymer bump or acompliant bump to electrically connect said other end of said singlelayer lead and said PCB pad.
 14. A packaging and interconnection of acontact structure as defined in claim 5, wherein one end of said singlelayer lead is connected to said PCB pad through a conductive polymer.15. A packaging and interconnection of a contact structure as defined inclaim 14, wherein said conductive polymer is a conductive adhesive,conductive film, conductive paste or conductive particles.
 16. Apackaging and interconnection of a contact structure as defined in claim14, wherein said conductive polymer is a conductive elastomer includingan anisotropic conductive adhesive, anisotropic conductive film,anisotropic conductive paste or anisotropic conductive particles toelectrically connect said other end of said contact trace and said PCBpad.
 17. A packaging and interconnection of a contact structure,comprising: a contact structure made of conductive material and formedon a contact substrate through a photolithography process, said contactstructure having a base portion vertically formed on said contactsubstrate, a horizontal portion, one end of which being formed on saidbase portion, and a contact portion vertically formed on another end ofsaid horizontal portion; a contact trace formed on said contactsubstrate and electrically connected to said contact structure at oneend, the other end of said contact trace being formed of a contact pad;a connection target provided at an outer periphery of the contactstructure to be electrically connected with the contact pad on thecontact trace; a conductive lead for electrically connecting an uppersurface of the contact pad on said contact trace and the contact target;an elastomer provided under said contact substrate for allowingflexibility in said interconnection and packaging; and a supportstructure provided under said elastomer for supporting said contactstructure, said contact substrate and said elastomer; whereinsubstantially all portions of said contact structure are projected fromsaid contact substrate to a free space to allow free movements of atleast said horizontal portion and said contact portion, and wherein saidhorizontal portion of said contact structure produces a contact forcewhen said contact structure is pressed against a contact target, therebyachieving a scrubbing effect on a surface of the contact target.